In certain material processing technologies such is those used in pharmaceutical and food processing, particulate feedstock material is formed as an intermediate product for use in further processing. The particles may be formed by various techniques. One technique is to spray dry eject product particles from a spray nozzle. This technique employs a spray nozzle supported within a tower. The spray nozzle converts liquid emulsions to dry powder at elevated temperatures. Conventional heated liquid emulsion is transported to the spray nozzle where it is ejected therefrom as a dry powder into a free-flow feedstream. As the heated dry powder falls in a free-flow condition, it cools and solidifies into particles. The particles may then be used for further processing in conventional material handling applications for the formation of food stuffs and pharmaceutical products.
In certain applications, there is a need to encapsulate certain feedstock products during the material handling process so as to form a product matrix. In the food processing industry, it is typically desirable to encapsulate food and bioaffecting additives such as pharmaceuticals, nutraceuticals, flavorings, colors and sugars in dissimilar food substances such as oleaginous material like fats or oils such as flavor oils. In the pharmaceutical industry, active drugs, vitamins and the like can also be encapsulated in fats and oils. The encapsulation of product additives has certain benefits. The encapsulating substances can act as a taste mask to improve the organoleptic qualities of the food product and also to taste mask certain bitter-tasting drugs. Encapsulating can also prevent unintended volatilization of the actives over time. Furthermore, the substances which encapsulate the drugs can act to deliver them in a time-release fashion.
One technique to provide an encapsulated product matrix is to form the encapsulated product in an extrusion process. An encapsulant such as fat is typically processed in an extruder under controlled heat and pressure. The fat is liquefied or molten and forced through extrusion dies to form round bead or sphere-like particles. Additives may be introduced into the fat during the extrusion process so that the small formed beads include the additive encapsulated within the fat.
This extrusion process serves adequately for many products in the food and pharmaceutical industries. However, the method has certain limitations. In an extrusion process, it is difficult to obtain high loading of the additive material into the fat spheres. The process itself limits the amount of additive which can be introduced into the oleaginous material as the product undergoes extrusion. Further, certain additives which are desirable to be encapsulated with fat exhibit an extremely low melt point. Thus, during the heated extrusion process these low melt additives may have a tendency to break down, or degrade. Additionally, certain desirable additives are resistant to melt flow. Thus these additives are especially difficult to incorporate into a fat sphere during a heated extrusion process. Furthermore, the high heat which must be applied in the extrusion process may have a tendency to effect a reduction in the flavor quality of certain additives. Thus, it may be appreciated that certain additives are not particularly well-adapted to being processed in an extrusion process.
In addition, the necessity of first spraying liquid emulsions, and then encapsulating them via an extrusion process of ten necessitates two or even more separate and distinct pieces of equipment. Distinct equipment such as spray dryers, congealers, fluidizers, extruders and evaporators translates into additional overhead and processing costs. Therefore, it is desirable to provide a process for manufacturing fat encapsulated additives wherein the additives retain desirable product qualities and do not deteriorate during the material processing. It is furthermore highly desirable to accomplish this with one self-contained piece of equipment.